"Using a Mac may certainly be a safer choice for a lot of people as despite being vulnerable they are not targeted. However this is not the same as Macs being secure, something Eric Schmidt erroneously advised recently. I may be able to browse impervious to malware on a Mac at the moment, however I personally would not be comfortable using a platform so easily compromised if someone had the motivation to do so. In this article I address just why OS X is so insecure including the technical shortcomings of OS X as well as Apples policies as a company that contribute to the situation."

Everything he says about OSX is true, but he didn't really examine windows security in depth. It was designed less secure than he thinks and ultimately implemented even less securely.

HIs biggest complaints seem to be the lack of ASLR, sand boxing and apple's past response to security threats. Then, in the conclusion he mentions that all of these are being addressed in Lion. That's bold writing right there: arguing that a company should do exactly what they just told you they should do!

First user is "owner\sudoer\wheel" browser allows arbitrary code, pdfs run at an exec level, Broswer unstuffs and mounts .dmg\.iso files - I guess that would be bad, firewall is off, guest accounts are on iLife services sharing on a bunch of porst and just a bunch of other stuff. I am a big Apple head, and the Non-Admin accounts is with Limited and Parental Controls on is nice but the Admin account is a nightmare.
BUT that is again hard to patch against the stupid user. Unity as an interface took a beating but it makes it harder for a curious newbie to assassinate his configuration. And it seems plenty secure with user defaults.